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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Posted on 15 May 2010 by John Cook

In the past, research has predicted that global warming could lead to the extinction of more than one-fifth of animal and plant species. This research has largely been based on theoretical models. However, now observations can confirm whether reality matches theory. The paper Erosion of Lizard Diversity by Climate Change and Altered Thermal Niches (Sinervo 2010) compares global observations of lizard populations from 1975 to present day. The result? Rapidly warming temperatures are causing lizard species to go extinct before our eyes.

How does climate change affect lizard populations? While lizards bask in the morning sun to warm up, they retreat to the shade when temperatures get too hot to avoid heat stress. As it gets hotter, they have less time to forage for food. Warmer springs are particularly devastating as this is when lizards reproduce and need extra food.

Sinervo 2010 first analysed observations of lizard populations in Mexico. Since 1975 when observations began, 12% of local populations have gone extinct. Looking at weather station data, they found a correlation between the change in maximum temperature and local extinctions. The number of hours that lizards were forced to retreat to shade were significantly higher at extinction sites.

There are two ways species can compensate for climate change: adapt or migrate. Temperatures are changing too rapidly for most species to evolve in order to adapt to warmer temperatures. That leaves migration. What is being observed is species are relocating to cooler regions in response to warming temperatures. Lizard populations from lower elevations are expanding up to cooler, higher habitats. This appears to be exacerbating extinction of species already living in higher elevations.

Another important result they found is if we manage to reduce CO2 emissions over the next few decades, this will reduce the number of species extinctions in 2080 but have little effect on the extinctions by 2050. A slow down in global warming will lag atmospheric CO2 levels by decades. This lead the authors to conclude that lizards have already crossed a threshold for extinctions.

Comments

What's too bad, is that lizards aren't as photogenic as polar bears or other endangered species. So they can't be used as a mascot for "stop the warming" campaigns, but the best evidence now does suggest that they are in direct danger.

I love lizards. In fact, I prefer them to polar bears. They're much more user friendly and much less likely to maul you if you accidentally intrude on their territory.

However, extinctions are a reflection of natural selection without which evolution would not occur. More adaptable organisms thrive - the less adaptable decline or occupy specialised ecological niches and are hence vulnerable as conditions change.

Extinctions have always happened and will always happen even as new species gradually appear. While the contribution of AGW is undesirable, we should be wary of excessive reliance on what is ultimately an emotive invocation of romanticised illusions about nature.

For my part, I'm always fascinated by nature's resilience in the face of the ugliest of human structures - clumps of ferns and moss growing between the bricks of a prison wall spring to mind as does the blue tongue lizard which found a comfortable home underneath a concrete slab in our garden.

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Response: People have died naturally in the past but that doesn't make murder okay. Just because bad things happen naturally doesn't absolve us of responsibility when we're the cause.

Re nature's resilience, the empirical evidence from this study and past periods of dramatic climate change find that many species simply cannot adapt fast enough when temperatures warm too quickly.

chriscanaris,
the problem is not the interest on any particular specie nor the fear that nature as a whole won't be able to cope with it one way or another. It's the signs and consequences of global warming and if we humans will fare better or worse.

chriscanaris: "However, extinctions are a reflection of natural selection without which evolution would not occur. More adaptable organisms thrive - the less adaptable decline or occupy specialised ecological niches and are hence vulnerable as conditions change."

Do you include rainforest in that, and can I conclude that trees are just an inconsequential victim of the highly adapted organisms known as the chainsaw and bulldozer?

John is this strictly accurate? Does this paper describe extincts or range changes? I have a real issue with the liberal use of the word extinction in this paper.

00

Response: I had a whole section distinguishing between local extinction (the dying out of a species in a region) and species extinction. I left it out to keep the post streamlined, figuring it would come up in the comments. The 12% of extinctions in Mexico refers to local extinctions. They predicted that local extinctions will reach 39% by 2080. This equates to 20% of total species extinctions.

One should never use the term 'local extinction' in any form or context. It is an oxymoron. The day that some over-zealous academic biologists took up the term was a step backward in science and the public understanding of it. If something is only 'locally exctinct', then it is not extinct, by definition. The use of the term should be banned from all biological literature becuase it creates so much distortion and exageration.

I have repeatedly come scross this problem in policy circles when various pro-green advocates want to make and enforce various policies based on something that is by definition, not only ambiguous, but variable both in time and space. Without the time and space context, the data gets distorted, misapplied, and misused. Not only does the use of such a term ensure a whole bunch of out of touch academics (whose main job function seems to be to jump on every minutely possible thinly justified exageration of ambiguities), create all sorts of useless exagerations and distortions, but broader society then also suffers from the misuse and abuse surrounding the term. And once the term gets recycyled in various models etc in the fabulous peer reviewed literature system, all hope of anything approaching normality and reality is lost.

Ants are locally extinct in my kitchen every day, until the next day, as well as cockroaches, mosquitoes etc etc. The peer reviewed literature is riddled with this sort of nonsense, so many species have been catergorised as threatened, endangered, 'extinct', locally extinct, partially informally locally exctinct, (like informally partially pregnant), and so on, based on oxymorons and such like, that all resemblance to reality has been lost in the confusion. Time and spatial context of both species and broader ecosystem factors has to be applied to any discussion of species decline, but it usually isnt. Populations are dynamic, they decline and increase, they merge and split, but they don't go 'locally extinct', ever, not even once.

The same goes for the Mexican paper on lizards. No only does it ignore the issue of local decline, or local 'non-extinction', but it blunders further by blaming it all under the c02 bandwagon.

thingadonta, light is rarely shed on a subject by ranting. Wouldn’t it help to read the paper before blasting off inappropriately?

(i) “local extinction”. This is a perfectly sound and useful descriptor. The observation of the loss of a species from a particular regional habitat allows for a rational analysis of cause (habitat destruction, ecosystem imbalance, climate change, disease etc.). If causal influence(s) are identified then it’s possible to predict what is likely to happen to the same or related species in similar habitats elsewhere in response to similar perturbation.

(ii) “warming-induced local extinction”. Not sure what your “blaming it on the CO2 bandwagon” refers to! In reality, Sinervo et al. analyzed populations in 200 sites in Mexico. In these otherwise intact habitats the common element of lizard species loss is a large increase in Winter Spring temperature. The temperature rise and associated local loss of lizard species maps onto the independently determined “climate surface” (i.e. warming map).

This association of high Winter Spring warming with local extinction allows for a predictive model. Simply put, one can assess regional Winter Spring temperature rises throughout the world and predict regional habitats where related lizard species will be expected to struggle. This was done and existing and new records of lizard species loss throughout the 5 continents of the world were compared with the predictions. The match is strong. In other words throughout the entire world, global warming, especially enhanced Winter Spring warming is causing the loss of lizard populations.

(iii) local re global extinction. Several lizard species are already extinct (globally) during the last 100 years. This may not be due solely or even predominantly to global warming (I’m not an expert in this subject!). However it is obvious that extinctions are generally not “on-off” “here today, gone tomorrow” events (outwith bolide impacts, and mass slaughter; e.g. the final passenger pigeon populations already denuded by habitat loss). Global extinctions, especially under the influence of progressive environmental insult (global warming; habitat fragmentation and destruction) are very likely to be observed locally in advance of progressive spread to other habitats as the environmental impact (global warming in this case) advances. And of course in an increasing number of cases global and local extinctions are synonomous since many species are only defined by a local population – this is increasingly the case as a result of habitat fragmentation.

Seems to me that locally extinct is distinctly distinguishable from globally extinct. I think you may be picking up more on semantic issues given that local extinction is just another (informal) way of describing extirpation

Personal Comment: mammals are not naturally attracted to cold-blooded animals but if we get over that bias we quickly come to the realization that these creatures are still an indicator species (indicating that 6.9 billion people are changing the environment). So here is a question for people who are still okay with the extinction of lizards: these creatures eat a lot of insects. When one of our enemies (insects in our crops) looses their enemy (lizards), then we have lost a friend.

It's diffult to me to understand the point of local vs global extintion. Afterall it seems quite obvious. For sure, if not extinct, other terms could be used; for example "disappeared" or "are not to be found", but then what? Aren't they synonyms? Should i not use extint volcano or fire until all the active volcanoes or fires disappear from the earth?
English is not my mother language so maybe I'm missing this subtlety. But as far as I can tell it's quite a silly argument.

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Response: I think the point of the comments on local extinction/species extinction is that if we can get into a trivial debate about semantics, people will be distracted from the fact that animal species are currently being wiped out by warming temperatures all over the world.

I've never really understood that passive acceptance and intellectual rationalisation of species extinction along the lines that.....extinction has always happened; it's natural selection; extinctions lead to new species etc. etc.).

It's totally divorced from extant reality, makes no distinction between magnitudes and has an underlying confusion over the nature of speciation, all of which takes it into a sort of inhuman realm.

The reality is that species extinctions are occurring at a massively faster rate than the background extinction rates. This has been largely due to habitat destruction and direct extirpation in the past, but global warming is joining these as a combined insult against the natural environment. Since (i) temperatures are rising at a rate that is faster than the ability of many species to adapt, let alone evolve, and (ii) habitat fragmentation has greatly limited the possibilities for migration to compatible habitats, this situation is very likely to worsen. That's the extant reality.

To intellectualize this in terms of natural selection and new evolutionary possibilities is to misunderstand the nature of evolution and especially the timescales involved, especially in relation to human timescales. Massive species extinctions during the coming two centuries (say) is not going to result in a plethora of new evolved species adapted to a warmed world. It will lead to a hugely impoverished natural environment. If we became able to stabilise the situation at some time in the future (say 200 years down the road when we will certainly have had to wean ourselves of fossil fuels), the recovery of the natural environment will occur on timescales of thousands to 100's of thousands of years. However intellectually pleasing it might be to consider that interesting long term future, it lacks a human dimension.

So I doubt future populations will be so keen on the environmental legacy that the sort of blase acceptance your posts describe would lead to. Personally, I don't think things will develop to such dismal state.

A couple of comments on this thread do a bit of hand waving about "natural selection", the analogy of "it's all cyclical" in AGW denial, and jump to an extraordinary conclusion that there's no problem or things aren't so bad as some greenies and over zealous scientists would have us believe.

Based on research by the Zoological Society of London, it reports that the number of land vertebrates has declined 33% since 1970. It is beyond my understanding how this figure is not shocking. Even if we say, divide this figure by two, it is still shocking and manifestly unsustainable.

This is just an illustrative factoid, and the whole thing should be read.

That biodiversity is under very serious threat is beyond doubt. Currently it's a race to the bottom to see if climate change can overtake existing causes such as direct habitat destruction as the number one cause.

Thanks John, it's what i suspected but couldn't be sure. ;)
Putting aside the semantic issue and the meaning of global or local extintion, the natural rate of extinction is belived to be about 100 to 1000 lower than what we observe now and we're largely (10 to 100 times) above what may be considered a planetary boundary. Still waiting to find a 100 times speed up of speciation ...

"Extirpation" is a perfectly good word, except that most people don't know what it means. "Local extinction" is much more understandable. It's unfortunate that some people will shorten this to "extinction" because people are bad with details. I tend to find misuse of words to be quite annoying, like when someone confuses endemic with indigenous, but in the case of "extinction" versus "local extinction", it's not a big deal. Here's why:

"Local extinction" refers to the extinction of a population. What's a population? It's a group of interbreeding individuals of the same species that is isolated from other such groups. "Extinction" refers to the loss of species. What's a species? Basically it's a population that is sufficiently isolated from other groups to be recognized with a different name. It's a fairly arbitrary line, in practice.

What is lost when a species goes extinct? A genetic lineage is lost that can't be replaced by extant organisms, and biodiversity is reduced. What is lost when a population goes extinct? The same thing, but to a degree that our taxonomy won't recognize the loss.

There are other ways to argue about species versus population extinction. A metapopulation argument might take the form: "loss of a population is a quantifiable step toward extinction of the others." But these arguments aren't very satisfying. What's important is that there is objective evidence that the tree of life is being trimmed back, and it won't regrow any time soon. If I were a denier, I wouldn't focus on denying the loss of biodiversity -- they're going to lose that argument (as they did with the US Endangered Species Act which now protects unofficial 'species' ['distinct population segments' and 'evolutionarily significant units']). Nope, I would focus on biofunctionality ... niche extinction (or niche extirpation, if you like). Atlantic gray whales go extinct? We can transport Pacific gray whales, and they'll do the same kind of thing. Who needs polar bears? Grizzly bears are pretty similar. It's the same tactic as arguing about species versus populations, but it sets the bar much lower. That's what I would do, if I were a denier.

PS. In the sentence that #5 pointed out, John has "lead" when he should have "led".

Here's an analogy that might get me banned. But I can't resist the terrible ethics suggested by the "extinction-is-natural" crowd. Here goes:

The neighbour's daughter comes seeking refuge because her dad is very drunk, and when he gets very drunk, he rapes and beats her. She is offered protection against her dad by a sober host, but this host then rapes her. At trial the host uses, "She was getting raped and beaten anyway, at least I didn't beat her" as a defense.

Okay, that's pretty bad. I hope everyone agrees. But in the case of anthropogenic extinction that is being defended, she is getting raped AND beaten by the host, and this is happening at least 10x more frequently.

I'm sorry if this is too offensive. Feel free to delete. There's no science in it.

Here's an analogy that might get me banned. But I can't resist the terrible ethics suggested by the "extinction-is-natural" crowd.

It doesn't offend me, but I don't think it's a particularly helpful analogy.

How about this:

People die all the time, so as Randy Newman sang many years ago, "let's drop the big one, and see what happens ..."

I mean ... it's only a rate-of-death difference, right? Nuclear holocaust vs. the background rate of death. Just as we're talking about a rate-of-extinction difference. No biggy. People are going to die anyway. Some will live, others will be born.

Your preceeding post was a very good summary of the biology-based position.

And quokka's got it exactly right when he says:

A couple of comments on this thread do a bit of hand waving about "natural selection", the analogy of "it's all cyclical" in AGW denial...

I'm pretty sure even paleontologists refer to classes of organisms having 'gone extinct' in certain areas but not others when the record shows they were once more widespread (e.g., marsupials almost everywhere except Australasia).

I have to agree with thingadonta. There is no such thing as local extinction. Here's the start of Wikipedia's description of extinction.

"In biology and ecology, extinction is the end of an organism or group of taxa. The moment of extinction is generally considered to be the death of the last individual of that species"

Now Wiki isn't the font of all knowledge but this seems fairly accurate. It's pretty much an all or nothing thing extinction, go to the Red List and you see it used in a very specific way. They'd be looking at maybe 10 years of no sightings before a species is called extinct. This paper in many cases has had 2 people search in a locale for 4hrs before making the call. What happens if local conditions change sufficiently to allow re-introduction of the species into the area? Is this de-extinction?

All that is happening is that the word losses any real scientific meaning. But why do this? There is a reason that science uses well defined terms, it gives clarity to ideas. Why abandon that? It really does seem that in this case it's to gain greater publicity for the paper. Call it range change and it might get picked up by New Scientist. Call it extinction and you get yourself an article in the NY Times.

This isn't just a semantic arguement. John's headline is an example as how poor definition in the paper leads to headlines that are alarmist in the context of the work presented. I'd contest there are no "Species extinctions happening before our eyes" in context to the work presented.

The term 'local extinction' is a terrible term. It's like partially pregnant. The correct term should be locally absent, or locally displaced, or locally 'not observed in this survey', and so on. There is therefore no connotation of whether the species use to be there or not, whether land use patterns have changed (you dont see any koalas in Sydney CBD) and it also takes the important step in placing a value on competing land use/land use changes. This is the key issue. Nobody cares if there are no koalas (locally displaced/absent, not locally extinct) in Sydney's CBD.

Despite the fact the academics dont want us to 'value' a species, in reality this goes on all the time. We don't tear down all the buildings in Sydneys CBD and replace the locally absent koalas, because of purely socio economic reasons. So all species have, like it or not, a socio economic value. This is also why stopping dams simply because of a 'locally absent' fish is limited in scope (I hesitate to say plain wrong) because it doesn't place a overall value on the socio-economic benefits of the dam. Everything has a relative value, and humans chose betweeen them, all the time.

Don't get me started on other things, like whether temperate forests have less 'value' because they have less biodiversity than tropical forests, or whether nature somehow favours biodiversity in any case, or whether we should reduce biodiversity in Africa and tropical rainforests to reduce disease rates and malaria, because these are off-topic.

But 'local extinction' is not just a semantic issue. Most of the distorted figures on extinction rates are based on such misuses, and abuse of such terms. Academics who just say it is 'semantic', are in effect, protecting their narrow interests and the ongoing charade about extinction rates and the relative value of different species in a whole-of-land use context, with the eg lack of socio economic context in bioregional studies, and the level of overall relative declines/increases of ecosystems as a whole in a broader region in relation to other land uses (such as within the context of increasing urbanisation in Mexico), and so on.

'Locally extinct' is by definition, internally inconsistent, a self-contradiction. I thought skeptics were the ones full of inherant self contradictions and and inconsistencies(ie they haven't yet 'smoothed' out the data to make people feel more comfortable).

thingadonta, please just look up the definition of "population." The ecological definition includes "...occupying a particular geographic area."

"Extinction" means vanishing of a population. You can say "extinction of the population that lived in area X." To generalize that phrase to describe multiple such cases, you can say "local extinctions."

Biologists have been using the term "local extinction" for a really long time, for reasons having nothing to do with AGW. They have found it useful. The fact that you, a non-biologist, do not find it useful is not relevant to the term's use by biologists.

I think I must have some bad copies of Microsoft-Windows or Adobe-Acrobat, because I cannot find any reference to Carbon Dioxide in this paper. Is it in the supporting information (peer reviewed or otherwise)?

Alternatively, if the premise of the article is simply: "If temperatures go up a bit then lots of Lizards will die", then it fills me with admiration for all those dinosaurs who stuck it out for so long.
(Not to mention all the 'Mad Dogs amd Englishmen who Go Out in the Midday Sun').

However, there is an even worse conclusion that could be drawn. Temperatures at Football World-Cup competitions have risen since 1966, and England have never won the World-Cup since. This makes sense because the English players (just like reptiles) are not well equiped to handle the heat.
The prognosis is, therefore, grim. England may never win another world cup because of CO2 induced "global-warming".

00

Response: The last two sentences of the paper are:

Although global efforts to reduce CO2 may avert 2080 scenarios, 2050 projections are unlikely to be avoided; deceleration in Tmax lags atmospheric CO2 storage by decades (4). Therefore, our findings indicate that lizards have already crossed a threshold for extinctions.

Re dinosaurs, when temperatures have changed dramatically in the past, our planet has experienced mass extinctions. It's the fast pace that is the killer - animals are not able to evolve or migrate quickly enough to adapt.

re Response "It's the fast pace that is the killer - animals are not able to evolve or migrate quickly enough to adapt."

What validation is there for that statement? Many animals, insects or birds are able to migrate very quickly, especially if they are considered pests which seem able to migrate at a faster pace than humans are able to track them.
Pests introduced from England quickly overrun Australia even into the hotter arid regions totally different to the English climate. The biggest obstacle may be lack of suitable habitat, lost through reasons other than AGW.
Native species are often threatened not because other invading species are too slow to adapt, but because they are far too fast.

00

Response: How do we know that fast climate change leads to mass extinctions? Past history. The fossil record shows us that mass extinction events coincided with periods of dramatic climate change. For more details, follow the link in my previous response.

Tom Dayton (#20): Thank you very much, but I have read the 4th paragraph, and it did not answer my question ('how many new local lizard populations have appeared...'). It suggests there are difficulties with migration, but no facts are presented.

I am not convinced that they bothered to look for any new populations. On the contrary, the abstract (in the given link) only states they have studied 200 existing sites (in order to see what happened with them). The purpose of the study is to show that local populations go extinct, not to look for new ones forming elsewhere.

There are any number of reasons why your rosy picture is all wrong. Australia has quite a diverse flora. Some of the reasons include variety of climatic conditions and variety of soil types. The Sydney area for example has a considerable variety of plants adapted to soils over a sandstone base. These populations cannot necessarily pick up their roots and move a few hundred km south if things get a bit toasty for them. And no doubt some of the species of insect that depend on/and are depended on by those plants cannot set sail for more amenable climates without those plants.

Rain forests in SE Queensland grow on soils on a basalt base. I've seen a couple of places where the transition from rain forest to dry sclerophyll is so abrupt that you would swear that somebody had built a fence. It's the edge of the old lava flows. Again, relocation for better climate may not be an option.

The point is that ecology is complex, far more complex than making rather unjustified inferences from the fact that rabbits and foxes overran Australia. There will always be some species that are as tough as old nails and will survive "anywhere", even in conditions of extreme loss of biodiversity.

quokka at 19:34 PM, I was asking if there was any validity in the statement animals are not able to evolve or migrate quickly enough to adapt.
If fauna can evolve into flora in nature as quickly as it seems to have from my post to yours, then it suggest that there is no validity in the original statement. ;-)

Argus, the scientists chose a sample of sites spanning a range of typical temperatures, and chose multiple sites at each of those typical temperature levels.

They inventoried lizards of all species at all those sites. In other words, the scientists were indeed looking for new populations forming elsewhere. As John's post says, "What is being observed is species are relocating to cooler regions in response to warming temperatures. Lizard populations from lower elevations are expanding up to cooler, higher habitats. This appears to be exacerbating extinction of species already living in higher elevations."

That means the scientists observed (those are the "facts" you are looking for) new populations in the cooler sites. In other words, the scientists did look for, observe, and report that new populations formed.

But each new population competes with the extant population, helping to drive the extant population to extinction.

That domino process peters out at the coolest end of the habitat range, where the extant populations tend to just disappear instead of migrate. That's because a habitable zone for lizards must have more than the right temperature. Other animals, and plants, do not migrate at the same pace, and in many cases never do. Cooler sites also tend to be higher altitude sites, entailing a whole lot of differences other than temperature (humidity, precipitation, soil composition, ultraviolet radiation, temperature extremes, predators, prey, ...). Meanwhile, back at the hottest end of the site range, there are few populations moving in, because there aren't any sites for them to come from.

Thingadonta, please read the paper and stop blustering about things unrelated. As the study states explicitly, as does the accompanying commentary and my post you responded to, the areas studied were otherwise intact habitats. So this isn't about ants in your kitchen or koalas in Sydney CBD. It's not about tearing buildings down to reintroduce koalas, nor about "socioeconomic values". And "local extinction" is nothing like "partially pregnant" which is an objectively meaningless term.

If you read the paper in the context that the Earth has something like 45% of its land area still in the form of wilderness, then in areas that have rather little local human impact (and some that do) many species of lizards across the 5 continents of the world in many habitats are struggling to cope with the enhanced Spring temperatures in a warming world. In 12% of the habitats, and more so in other regions of the world, many of these lizard species have disappeared from these habitats entirely. They are locally extinct. The common factor is warming.

Many animal species are in danger of extinction and many have already gone extinct [*]. Some of these are lizards. Several of the lizard species studied by Sinervo et al are on the Red List of Threatened Species, and the incremental loss from local habitats is a potential harbinger of full extinction, since that scenario has already been played out for other now extinct species. If we are going to understand the nature of contemporary extinctions, their causes and the increasing impacts of global warming then we might as well take the science seriously.

-------------------------------
[*] According to this paper "In late 2007, there were 41,415 species on the International Union for Conservation of Nature Red List, of which 16,306 are threatened with extinction; 785 are already extinct."

Yes, John, my bad (#29). CO2 was there in the penultimate sentence. I shouldn't try and do science on a Saturday night.

Some of the later posts re-ignite a question I've asked of geologist-friends before, but not got a satisfactory answer to.
That is: Did a large meteorite (as measured by Iridium distributions) cause the mass extinction of the dinosaurs (I'm not sure if this is what is meant by the Permo-Triassic extinction)?
Or was it something else? I've also read that the extinction occurred over a period of greater than a million years, which doesn't seem much related to a cataclysmic impact of either climate or meteorites.

sorry, batsvensson; I drifted into British yoof colloquialism! I meant "massive" in the sense of "large".

It's not straightforward to determine extinction rates, and these are presumably always estimates (both of the natural background rate and whatever current rate one is attempting to compare). However estimates of current extinction rates put these at 10's to 100's of times the background rate.

frogstar, there has apparently been a long standing uncertainty over whether it was the Chicxulub asteroid impact, or an earlier (or later?) impact whose crater hasn't been found (under the sea?), or whether the massive flood basalt eruptions that produced the Deccan Traps in now-India was responsible (or a major contributor; e.g. the Deccan Traps resulted in a long term stressing and the impact delivered the coup de gras).

Very recent reassessment of all the data seems to point to the Chicxulub asteroid impact being the cause of the end-Cretaceous extinction that did for the dinosaurs 65 MYA (and set the stage for the wonderful world of mammals!).

The Permian-Triassic extinction was 251 MYA and was a particularly brutal mass extinction.

Migration has it's limits as well. It is well within the realm of possibility that some species will have no place to migrate to and will finally go extinct (some migrations being vertical while others follow a lateral pattern). Some species will go extinct as a result of being displaced by the migration of other species. And let's not forget the other pressures we place upon species through loss of habitat and pollution. Someday we may find ourselves on the "endangered species list".

Quote:"Noting that the world has failed to meet its target to achieve a significant reduction in the rate of biodiversity loss by 2010, the report stressed that with the current rate of biodiversity loss, there will be “a severe reduction of many essential services” provided by nature to human societies, as ecosystems reach their limit and shift to alternative, less productive states, “from which it may be difficult or impossible to recover.”"

The complaints about the term "local extinction" seem to me to be missing the point. The regional loss of a species can have huge repercussions, both for other plants and animals and for humans who rely on them. (It could even have consequences for tourist economies, in some areas.)

Re-introducing a species may be possible, depending on how much time has passed, whether the problem that caused the initial extinction has been solved, etc. If AGW is the problem, it could be some time before re-introduction is feasible, to put it mildly.

(Which reminds me: One of the stranger tendencies on the "skeptic" side is to claim, often simultaneously, that extinction is perfectly normal, and that a given animal or plant will be fine because it'll simply adapt to AGW. I'm not sure you get to have it both ways.)

"The fossil record shows us that mass extinction events coincided with periods of dramatic climate change."

As an environmentalist (dynamic ecology) I have to take a voice.
The emergence of human civilization has led to the great extinction (which takes out) by:
1. Sharp reversal of natural ecosystems to agriculture.
2. Habitat fragmentation (anthropogenic barriers hindering migration in the case of climate change - temperature), and depletion of natural environments (the exploitation and pollution).
Under these conditions, any even the smallest variation in temperature can lead to the extinction of many species.
... but:
1. Current temperature change is indeed, but not violent. Her "unprecedented" is long-term sustainable growth temperatures.
2. Remember that it is always cool = reduce the number of species - selection, warming = adaptive radiation; ecosystems with the greatest biodiversity is warm ecosystems. Arctic Ecosystems area (the NPP) are often based only on a few species of algae. Indeed it is often (NPP) greater than in the tropics, in tropical al is their (algal species), hundreds ... Interestingly, even the polar bears were created during one of the interglacial’s - allowing the expansion to the north of Grizzly Bear.
Conclusion: warming (at current rates) will help considerably larger number of species to survive the current anthropogenic pressures and lead to the elimination of rare species, as a rule, and so are at the end of its "evolutionary road".
3. Studies targeting potential adaptive responses to changes in temperature, are often fragmented and concern over a short period of time (at least claims about the oceans, professor Jean-Pierre Gattuso - Programme Arctic EPOCA). Geological studies are too vague.

"For example an assessment of amphibian extinction rates estimates this at more than 200 times the background rate."

In particular, insects and amphibians because of their enormous potential reproductive and breeding create a large number of so-called. "ephemeral species". Their "evolutionary life" has always been short (which uses such as Professor Tim Flannery).

"Did a large meteorite (as measured by Iridium distributions) cause the mass extinction of the dinosaurs (I'm not sure if this is what is meant by the Permo-Triassic extinction)?"

Probably all the great extinctions caused rapid cooling (no warming). The Permo-Triassic extinction - anoxia - is still only a "fashionable" hypothesis ...

So what do you need?
Instead of spending money to fight AGW, above all, should be used to reduce fragmentation of natural environments. In the past temperature changes were really sharp and I'm sure this will be in the future ...

On the whole 'local extinction is not extinction' bit... actually, this is not always true.

There are differing definitions of the word 'species', but most are close to the concept of a breeding population. However, we can't track the breeding habits of every animal in the world and don't really know if two animals from opposite sides of the planet would breed fertile offspring or not. Thus, we generally ASSUME that animals which LOOK alike are members of the same species. Modern genetic science has proved over and over again that this assumption is wrong as often as not.

In many cases what we call a 'local population' of a species is, in fact, a DIFFERENT species which looks very similar but has significantly different DNA and cannot interbreed. Read up on cryptic species to see what I'm talking about. Also a news article on a recent example of discovering that such a 'local population' was actually a separate species.

Thus we can be quite certain that some of these 'local extinctions' are in fact the TOTAL extinctions of distinct species which had just not been classified as such yet.

Wrong again Arkadiusz Semczyszak. Take a look at all the temperature proxies for the last 12,000 years & what do you see? I see temperature rises of a similar magnitude to recent warming-but over a period of CENTURIES OR EVEN MILLENIA! By modern day standards, these warming events have actually been incredibly slow. Even in all the previous Interglacial Periods where the planet was moving closer to the sun-& the change in temperature was on the order of 8 to 12 degrees Celsius-it was still occurring over tens of thousands of years (one warming event, 150 kyrs before the present, took 25,000 years for a 10 degree warming to occur-or +0.004 degrees per decade, nearly 20 times *slower* than in the modern age). So please spare us this talk about past warming being "really sharp"-they were actually quite dull compared to everything we're currently doing. Yet if these relatively *slow* warming periods could cause mass extinctions, then what potential for extinction is there in this more rapid warming phase?

Also, there is plenty of evidence to suggest that rapid methane release-& resultant *warming*-caused the mass extinction at the Permian/Triassic boundary, & a lot of evidence to suggest that the original Cretaceous impact that wiped out the dinosaurs probably led to "rapid" warming, before the planet got cold. So I'd suggest you need to check your facts a bit more carefully in future Arkadiusz.

Marcus
"... quantitative evidence for the presence of a Medieval Climate Anomaly (in this case, warm summers between AD 1150 and 1350; ΔT = +0.27 to +0.37°C with respect to (wrt) twentieth century) and a very cool period synchronous to the 'Little Ice Age' starting with a sharp drop between AD 1350 and AD 1400 (-0.3°C/10 years, decadal trend)... [!!!]" (2009). The present warming (last 50 years in the twentieth century) is not even half of that ...
In the nineteenth century, glaciers in the Alps were moving at a speed of (locally) up to 3-4 meters per day in one (...) destroying entire ecosystems.
Marcus - high time to abandon the Mann hockey stick ... Since 1998, science has changed ... Even the IPCC has said that the former does not change the temperatures were in the hundreds and thousands of years - L. Thompson - IPCC - "This abrupt event, ≈5,200 yr ago, was widespread and spatially coherent through much of the tropics and was coincident with structural changes in several civilizations. These three lines of evidence argue that the present warming and associated glacier retreat are unprecedented in some areas for at least 5,200 yr."
... and so I could enumerate dozens, dozens of works from the last years. Natural strong climate change is likely always been sudden.

If it's "high time to abandon the Mann hockey stick" then why do you guys keep obsessing about it?...and if as you say "Since 1998 science has changed" why do you ignore the wealth of data on this subject from the last 6 or 7 years, and continually hark back to 12 year old papers?

In fact no one talks very much about Mann et al 1998/1999 these days (although the data continues to be displayed in reviews on the subject that covers the entire paleoreconstruction field). After all this is 12 year old research and there have been numerous paleoreconstructions in the intervening years. These all yield pretty much the same conclusions about Northern hemisphere temperature as originally presented all those years ago.

I don't think any of them show what you suggest (what data are you referring to in your post?). I've had a quick look at the following reconstructions [***] (URL's available on request) and none of them show the odd features (periods warmer than 20th century between AD 1150 and 1350 and "sharp drops between AD 1350 and 1400". In fact none of them show maximum temperatures in the NH of the last 2000 years greater than the mid-20th century global average, and most of the published paleoreconstructions show temperature rises during the period AD 1350-1400. So what have you been looking at???